1. Field of the Invention
The present invention generally relates to the field of electrical connectors, and more specifically to an arrangement which mates a flat, flexible cable to a hard-board such that conjugate soldering traces on the cable and hardboard may be precisely aligned in the lateral direction by moving the cable relative to the hardboard in the longitudinal direction.
2. Description of the Related Art
Rigid and flexible members in the form of sheets or panels have been fabricated in a number of configurations which include conjugate electrically conductive leads or traces for connection of the members to each other at their edges. The members are mated such that the edge or connector portions of the traces are aligned, and pressed together to complete the interconnection. U.S. Pat. No. 4,453,795, entitled "CABLE-TO-CABLE/COMPONENT ELECTRICAL PRESSURE WAFER CONNECTOR ASSEMBLY", issued June 12, 1984, to Norbert L. Moulin, teaches how metallic buttons or dots may be formed on one or both of the conjugate surfaces of the traces to facilitate ohmic connection therebetween in response to applied pressure. Alternatively, the mating connector portions of the traces may be aligned, and interconnected by soldering.
The present invention particularly relates to a connector assembly including a hardboard having traces which terminate in soldering pads formed on a surface thereof, and a flat, flexible cable formed with traces which terminate in soldering fingers for alignment with the respective soldering pads when the cable is mated to the hardboard. Soldering of the fingers to the pads is performed after the alignment has been performed and confirmed. In a typical application including such a connector assembly, a daughterboard includes two hardboards fixed to each other back-to-back, with the soldering pads formed on the lower edges of the hardboards. A flat, flexible cable extends around the lower edge of the daughterboard, and is formed with parallel traces which terminate at their ends in soldering fingers which mate with the soldering pads on the two hardboards. Metallic dots such as disclosed in the above referenced patent extend downwardly from the traces away from the lower edge of the daughterboard, and mate with conjugate traces on a motherboard or pin type connector which plugs into a conjugate pin type connector mounted on a motherboard.
The flexible cable is easy to bend, twist, or shift parallel to its longitudinal axis enabling it to conform to a labyrinthine path interconnecting remotely mounted hardboards. However, it is hard to shift the cable laterally when it is pressed against the surface of a hardboard, especially when the cable has relatively sharp bends resulting, for example, from extending it around the edge of a daughterboard. This makes lateral alignment of the conjugate soldering portions of the traces on the cable and hardboard, which extend parallel to the longitudinal axes thereof, difficult to perform. Although a certain amount of lateral misalignment is permissible where there are a small number of relatively large traces, current technology enables the fabrication of a very large number of small, closely spaced traces, requiring a correspondingly high degree of precision in lateral alignment accuracy.